When making a call that is not urgent, there are numerous cases when the call should be made but does not require an interruption or otherwise inconvenience to the person being called. However, the person receiving the call must answer before the urgency of the call can be determined.
For example, a dentist office making a call to remind someone of an appointment does not need the call to be answered as leaving a voicemail message is sufficient. The person answering the call may incur not just an interruption but also financial cost, particularly if they are on a cell phone in another geographic region when they answer the call (incurring both long distance and roaming charges).
As an alternative example, a call from a live TV show to offer someone a chance to win a luxury vacation requires immediate answer. In this case the person answering would want to take the interruption even if on their way out the door.
Caller ID display is a commonly supplied and commercially popular feature in telecom systems for both business and personal use. With this feature, the telephone number and in some embodiments, a name asserted with this number is displayed on a telephone for an incoming call. With this information, a user may assess whether or not to accept an incoming call or to allow for other call handling such as voice mail to be supplied. The called user is thus given control to assess the priority of an incoming call in relation to his/her current context. A user can utilize this to partition their attention so that they will not be distracted by matters which are not deserving of immediate attention.
The person being called can ignore the call, possibly after looking at the Caller ID, and hope a message would be left or to be called again if the call was actually urgent. Alternatively, the person being called can ignore all calls that would cause interruption or inconvenience.
In some cases, there may be a pre-arranged agreement that a call should be left to ring and would only be answered after a certain number of rings. However, this does not inter-work with voicemail functionality as the call would be routed to voicemail or the voicemail needs to be changed to answer after a longer number of rings (in which case most callers would hang up).